(1) Field of the Invention
The instant invention relates to an improved battery clamp for a set of automotive battery jumper cables for connecting a weak battery to a stronger battery, and more particularly to an improved clamp for a jumper cable set which reduces the chance of an electrical arc when making the connection. Subject invention is a further improved version of the automotive battery jumper cable set described and claimed in my U.S. Pat. No. 5,601,452 issued on Feb. 11, 1997. That patent is incorporated herein by reference in subject patent application and will be referred to in subject patent application.
(2) Description of the Prior Art
It is well known that automotive batteries produce both hydrogen and oxygen gas as a result of being charged and discharged. These gases can potentially be ignited, causing an explosion. One potential cause of ignition can be sparks due to electrical arcs that can occur when connecting jumper cables to the battery terminals. Essentially, jumper cables comprise two electrically conductive cables with spring clamps at each end of the cables to releasably engage the battery terminals. Typically, an arc, or sparking occurs directly at the battery terminal when connecting the last, i.e., fourth, clamp to the respective battery. To reduce the chance of such sparks igniting the gases around the battery, jumper cables having remote switching devices locating well away from the battery terminals have heretofore been known in the art. In this regard, the U.S. Pat. No. 4,662,696 to Asbury, is representative of the prior art devices. The patent to Asbury discloses a battery jumper cable having a safety switch located intermediate the clamp ends of the cable. The switch is normally biased to the open position and includes a handle, which when depressed makes electrical contact between the leads of the battery cable. However, there is a need for an automotive battery jumper cable set which includes a self-contained switch as opposed to a remote switch.
The instant invention provides an automotive battery jumper cable set including an improved clamp which eliminates the need for a manually activated remote safety switch. The instant jumper cable set assembly comprises an electrically conductive wire which is terminated at one thereof by the improved clamp. As described in the above-mentioned patent, the improved clamp comprises a pair of gripping members each having a jaw end 14A and a handle end 14B and the gripping members are pivotably connected to each other about an axis 18 between the jaw ends and the handle ends. As fully described in my above-mentioned earlier patent, a torsion spring 20 is mounted on the gripping members for normally urging the jaw ends thereof each other, each of the jaw ends of the gripping members is provided with a copper jaw member for engaging and grasping the battery terminal and one of the jaws on each clamp is not connected to the cable. However, the other jaw of the improved clamp is electrically connected to the respective end of the cable via an encapsulated pressure switch. As mentioned in my above-identified patent, it is to be noted that only one of the four clamps needs to have the encapsulated pressure switch to prevent arcing. However, one can have an encapsulated pressure switch in all four clamps as well. The pressure switch is physically positioned between the copper jaw and the jaw end of the gripping member such that spring pressure provided by the torsion spring is operative for closing the pressure switch when the clamp is mounted on a battery terminal. One contact of the pressure switch is connected to the copper jaw and the other contact is connected to the cable. Both contacts are electrically localized within the encapsulated switch. Since electrical connection is completed inside the encapsulated switch, any potential spark is insulated within the switch. An in-line fuse or a circuit breaker may also be positioned in the cable to provide short-circuit protection. The improved switch according to the teachings of subject invention provides an enclosed space at the time of the closing of the pressure switch which is free of any gas and this avoids any explosion for any electric sparks or arcing.
Accordingly, among the objects of the instant invention are: the provision of an improved clamp for an automotive battery jumper cable set which eliminates arcing in the vicinity of the battery terminal; the provision of a battery jumper cable assembly which is terminated at least one end by the improved clamp of subject invention; and the provision of a battery jumper cable assembly including the instant clamp members and further including an in-line fuse or circuit breaker in the cable for preventing short circuits.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.